Terminal apparatus, base station apparatus, communication method, and integrated circuit

ABSTRACT

A terminal apparatus includes a receiver configured to receive, from a base station apparatus, a signal including first information for indicating a plurality of Quasi Co-Location (QCL) parameters associated with a plurality of reference signals, and receive, from the base station apparatus, a signal including second information for configuring one of the plurality of QCL parameters, and a monitor unit configured to receive a downlink control channel of a QCL parameter of the plurality of QCL parameters based on the first information and the second information.

TECHNICAL FIELD

The present invention relates to a terminal apparatus, a base stationapparatus, a communication method, and an integrated circuit.

This application claims priority based on JP 2017-057405 filed on Mar.23, 2017, the contents of which are incorporated herein by reference.

BACKGROUND ART

Currently, as a radio access method and a radio access networktechnology for the fifth-generation cellular system, in The ThirdGeneration Partnership Project (3GPP), technical study and standardsformulation have been conducted for Long Term Evolution (LTE)-AdvancedPro and New Radio technology (NR) (NPL 1).

The fifth-generation cellular system requires three anticipatedscenarios for services: enhanced Mobile BroadBand (eMBB), which realizeshigh-speed, high-capacity transmission; Ultra-Reliable and Low LatencyCommunication (URLLC), which realizes low-latency, high-reliabilitycommunication; and massive Machine Type Communication (mMTC), whichallows a large number of machine type devices to be connected in asystem such as Internet of Things (IoT).

In NR, a technical study of massive MIMO (Multiple-InputMultiple-Output), which uses a large number of antenna elements at highfrequencies to secure a coverage with a beamforming gain, is beingconducted (NPL 2, NPL 3, NPL 4).

CITATION LIST Non Patent Literature

-   NPL 1: RP-161214, NTT DOCOMO, “Revision of SI: Study on New Radio    Access Technology”, June 2016-   NPL 2: R1-162883 Nokia, Alcatel-Lucent ShanghaiBell, “Basic    Principles for the 5G New Radio Access technology”, April 2016-   NPL 3: R1-162380, Intel Corporation, “Overview ofof antenna    technology for new radio interface”, April 2016-   NPL 4: R1-163215, Ericsson, “Overview of NR”, April 2016

SUMMARY OF INVENTION Technical Problem

An aspect of the present invention provides a terminal apparatus capableof efficiently communicating with a base station apparatus, a basestation apparatus communicating with the terminal apparatus, acommunication method for use in the terminal apparatus, and acommunication method for use in the base station apparatus. For example,the communication methods for use in the terminal apparatus and the basestation apparatus may include an uplink transmission method, amodulation method, and/or a coding method, for efficient communication,decrease in complexity, and reduction in interference between cellsand/or between terminal apparatuses.

Solution to Problem

(1) According to some aspects of the present invention, the followingmeasures are provided. Specifically, a first aspect of the presentinvention is a terminal apparatus including: a receiver configured toreceive, from a base station apparatus, a signal including firstinformation for indicating a plurality of Quasi Co-Location (QCL)parameters associated with a plurality of reference signals; andreceive, from the base station apparatus, a signal including secondinformation for configuring one of the plurality of QCL parameters, anda monitor unit configured to receive a downlink control channel of a QCLparameter of the plurality of QCL parameters based on the firstinformation and the second information.

(2) A second aspect of the present invention is a base station apparatusincluding: a reference signal generation unit configured to generate aplurality of reference signals to be transmitted to a terminalapparatus; and a transmitter configured to transmit a signal includingfirst information for indicating a plurality of QCL parametersassociated with the plurality of reference signals, transmit a signalincluding second information for indicating to the terminal apparatusone or more of the plurality of QCL parameters, and transmit a downlinkcontrol channel of a QCL parameter of the plurality of QCL parametersbased on the first information and the second information.

(3) A third aspect of the present invention is a communication methodused for a terminal apparatus, the communication method including:receiving, from a base station apparatus, a signal including firstinformation for indicating a plurality of Quasi Co-Location (QCL)parameters associated with a plurality of reference signals, andreceiving, from the base station apparatus, a signal including secondinformation for configuring one of the plurality of QCL parameters; andreceiving a downlink control channel of a QCL parameter of the pluralityof QCL parameters based on the first information and the secondinformation.

(4) A fourth aspect of the present invention is a communication methodused for a base station apparatus, the communication method including:generating a plurality of reference signals to be transmitted to aterminal apparatus; and transmitting a signal including firstinformation for indicating a plurality of QCL parameters associated withthe plurality of reference signals, transmitting a signal includingsecond information for indicating to the terminal apparatus one or moreof the plurality of QCL parameters, and transmitting a downlink controlchannel of a QCL parameter of the plurality of QCL parameters based onthe first information and the second information.

(5) A fifth aspect of the present invention is an integrated circuitmounted on a terminal apparatus, the integrated circuit causing theterminal apparatus to perform: receiving, from a base station apparatus,a signal including first information for indicating a plurality of QuasiCo-Location (QCL) parameters associated with a plurality of referencesignals, and receive, from the base station apparatus, a signalincluding second information for configuring one of the plurality of QCLparameters; and receive a downlink control channel of a QCL parameter ofthe plurality of QCL parameters based on the first information and thesecond information.

(6) A sixth aspect of the present invention is an integrated circuitmounted on a base station apparatus, the integrated circuit causing thebase station apparatus to perform: generating a plurality of referencesignals to be transmitted to a terminal apparatus; and transmit a signalincluding first information for indicating a plurality of QCL parametersassociated with the plurality of reference signals, transmit a signalincluding second information for indicating to the terminal apparatusone or more of the plurality of QCL parameters, and transmit a downlinkcontrol channel of a QCL parameter of the plurality of QCL parametersbased on the first information and the second information.

Advantageous Effects of Invention

According to an aspect of the present invention, a terminal apparatusand a base station apparatus can efficiently communicate with each otherand/or decrease complexity.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram of a radio communication system accordingto an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a schematic configurationof a downlink slot according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating a relationship between a subframe, aslot, and a mini-slot in a time domain according to the embodiment ofthe present invention.

FIG. 4 is a diagram illustrating an example of a slot or a subframeaccording to the embodiment of the present invention.

FIG. 5 is a diagram illustrating an example of beamforming according tothe embodiment of the present invention.

FIG. 6 is a diagram illustrating a concept in which multiple referencesignals applied to a transmission beam are transmitted in one or morecells according to the embodiment of the present invention.

FIG. 7 is a flowchart illustrating an example of triggering a beam pairlink status reporting in a terminal apparatus 1 according to theembodiment of the present invention.

FIG. 8 is a flowchart illustrating an example of triggering a beamrecovery request in the terminal apparatus 1 according to the embodimentof the present invention.

FIG. 9 is a flowchart illustrating an example of monitoring a downlinkcontrol channel in the terminal apparatus 1 according to the embodimentof the present invention.

FIG. 10 is a flowchart illustrating an example of transmitting adownlink control channel in a base station apparatus 3 according to theembodiment of the present invention.

FIGS. 11A to 11C are conceptual diagrams illustrating examples of a casethat a downlink control channel region monitored by the terminalapparatus 1 is changed according to the embodiment of the presentinvention.

FIG. 12 is a schematic block diagram illustrating a configuration of theterminal apparatus 1 according to the embodiment of the presentinvention.

FIG. 13 is a schematic block diagram illustrating a configuration of thebase station apparatus 3 according to the embodiment of the presentinvention.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described below.

LTE (and LTE-Advanced Pro) and NR may be defined as different RadioAccess Technologies (RATs). NR may be defined as a technology includedin LTE. The present embodiment may be applied to NR, LTE and other RATs.Terms associated with LTE are used in the following description.However, the present invention may be applied to other technologiesusing other terms.

FIG. 1 is a conceptual diagram of a radio communication system accordingto an embodiment of the present invention. In FIG. 1, the radiocommunication system includes a terminal apparatus 1A, a terminalapparatus 1B, and a base station apparatus 3. The terminal apparatus 1Aand the terminal apparatus 1B are also referred to as a terminalapparatus 1.

The terminal apparatus 1 is also called a mobile station apparatus, auser terminal (User Equipment: UE), a communication terminal, a mobileapparatus, a terminal, and a Mobile Station (MS). The base stationapparatus 3 is also called a radio base station apparatus, a basestation, a radio base station, a fixed station, a NodeB (NB), an evolvedNodeB (eNB), NR Node B (NR NB), next generation Node B (gNB), an accesspoint, a Base Transceiver Station (BTS), and a Base Station (BS). Thebase station apparatus 3 may include a core network apparatus. The basestation apparatus 3 may include one or more transmission receptionpoints (TRPs) 4. At least some of the functions/processes of the basestation apparatus 3 described below may be functions/processes at eachof the transmission reception points 4 included in the base stationapparatus 3. The base station apparatus 3 may have a communicable range(communication area), controlled by the base station apparatus 3, tohave one or more cells to serve the terminal apparatus 2. The basestation apparatus 3 may configure a communicable range (communicationarea), controlled by one or more transmission reception points 4, tohave one or more cells to serve the terminal apparatus 1. The basestation apparatus 3 may also divide one cell into multiple Beamed areasto serve the terminal apparatus 1 in each of the beamed areas. Here, abeamed area may be identified based on a beam index used forbeamforming, or a precoding index.

The communication area covered by the base station apparatus 3 may varyin size and shape for each frequency. Moreover, the covered area may bedifferent for each frequency. A radio network, in which cells havingdifferent types of base station apparatuses 3 and different cell radiicoexist at the same frequency or different frequencies to form a singlecommunication system, is referred to as a heterogeneous network.

A radio communication link from the base station apparatus 3 to theterminal apparatus 1 is referred to as a downlink. A radio communicationlink from the terminal apparatus 1 to the base station apparatus 3 isreferred to as an uplink. A radio communication link from the terminalapparatus 1 to another terminal apparatus 1 is referred to as asidelink.

In FIG. 1, in a radio communication between the terminal apparatus 1 andthe base station apparatus 3, and/or a radio communication between theterminal apparatus 1 and another terminal apparatus 1, OrthogonalFrequency Division Multiplexing (OFDM) including a Cyclic Prefix (CP),Single-Carrier Frequency Division Multiplexing (SC-FDM), DiscreteFourier Transform Spread OFDM (DFT-S-OFDM), or Multi-Carrier CodeDivision Multiplexing (MC-CDM) may be used.

Furthermore, in FIG. 1, in the radio communication between the terminalapparatus 1 and the base station apparatus 3, and/or the radiocommunication between the terminal apparatus 1 and another terminalapparatus 1, Universal-Filtered Multi-Carrier (UFMC), Filtered OFDM(F-OFDM), Windowed OFDM, or Filter-Bank Multi-Carrier (FBMC) may beused.

Note that the present embodiment will be described by using OFDM symbolwith the assumption that a transmission scheme is OFDM, and use of anyother transmission scheme is also included in an aspect of the presentinvention. For example, the OFDM symbol in the present embodiment may beSC-FDM symbols (sometimes referred to as Single-Carrier FrequencyDivision Multiple Access (SC-FDMA) symbols).

Furthermore, in FIG. 1, in the radio communication between the terminalapparatus 1 and the base station apparatus 3, and/or the radiocommunication between the terminal apparatus 1 and another terminalapparatus 1, the CP may not be used, or the above-described transmissionscheme with zero padding may be used instead of the CP. Moreover, the CPor the zero padding may be added both forward and backward.

According to the present embodiment, one or more serving cells areconfigured for the terminal apparatus 1. The configured multiple servingcells include one Primary Cell (also referred to as a PCell) and one ormore Secondary Cells (also referred to as SCells). The primary cell is aserving cell in which an initial connection establishment procedure hasbeen performed, a serving cell in which a connection re-establishmentprocedure has been initiated, or a cell which has been indicated as aprimary cell during a handover procedure. At the point in time when aRadio Resource Control (RRC) connection is established, or later, one ormore secondary cells may be configured. Note that the configuredmultiple serving cells may include one primary secondary cell (alsoreferred to as a Primary SCell, PSCell). The primary secondary cell maybe a secondary cell capable of transmitting control information in theuplink among one or more secondary cells configured for the terminalapparatus 1. The terminal apparatus 1 may be configured with a subset oftwo types of serving cells, a master cell group (also referred to as aMaster Cell Group, MCG), and a secondary cell group (also referred to asa Secondary Cell Group and SCG). The master cell group includes oneprimary cell and zero or more secondary cells. The secondary cell groupincludes one primary secondary cell and zero or more secondary cells.

Time Division Duplex (TDD) and/or Frequency Division Duplex (FDD) may beapplied to the radio communication system according to the presentembodiment. A Time Division Duplex (TDD) scheme or a Frequency DivisionDuplex (FDD) scheme may be applied to all of multiple cells. Cells towhich the TDD scheme is applied and cells to which the FDD scheme isapplied may be aggregated.

A carrier corresponding to a serving cell in the downlink is referred toas a downlink component carrier (or a downlink carrier). A carriercorresponding to a serving cell in the uplink is referred to as anuplink component carrier (or an uplink carrier). A carrier correspondingto a serving cell in the sidelink is referred to as a sidelink componentcarrier (or a sidelink carrier). The downlink component carrier, theuplink component carrier, and/or the sidelink component carrier arecollectively referred to as a component carrier (or a carrier).

Physical channels and physical signals according to the presentembodiment will be described. Note that the downlink physical channelsand/or the downlink physical signals may be collectively referred to asdownlink signals. The uplink physical channels and/or the uplinkphysical signals may be collectively referred to as uplink signals. Thedownlink physical channels and/or the uplink physical channels may becollectively referred to as physical channels. The downlink physicalsignals and/or the uplink physical signals may be collectively referredto as physical signals.

In FIG. 1, the following downlink physical channels are used fordownlink radio communication between the terminal apparatus 1 and thebase station apparatus 3. The downlink physical channels are used fortransmitting information output from the higher layers.

-   -   New Radio Physical Broadcast CHannel (NR-PBCH)    -   New Radio Physical Downlink Control CHannel (NR-PDCCH)    -   New Radio Physical Downlink Shared CHannel (NR-PDSCH)

The NR-PBCH is used by the base station apparatus 3 to broadcast anessential information block, such as a Master Information Block (MIB)and an Essential Information Block (EIB), which includes essentialsystem information (Essential Information) needed by the terminalapparatus 1. Here, one or more essential information blocks may betransmitted as an essential information message. For example, theessential information block may include information indicating some orall of a frame number (System Frame Number: SFN) (e.g., informationabout a location in a superframe including multiple frames). Forexample, a radio frame (10 ms) includes 10 subframes each having 1 ms,and the radio frame is identified by a frame number. The frame numberreturns to 0 at 1024 (Wrap around). Furthermore, in a case that theessential information block different every area within the cell istransmitted, each essential information block may include informationcapable of identifying the corresponding area (for example, identifierinformation about a base station transmission beam constituting thearea). Here, the identifier information of the base station transmissionbeam may be indicated by using an index of the base station transmissionbeam (precoding). In a case that the essential information block(essential information message) different in every area within the cellis transmitted, each essential information block may include informationcapable of identifying a time location within the frame (for example, asubframe number at which the essential information block (essentialinformation message) is included). That is, the essential informationblock may include information for determining each of the subframenumbers at which the respective essential information blocks (essentialinformation messages) using indexes of different base stationtransmission beams are transmitted. For example, the essentialinformation may include information needed for connection to the cell orfor mobility.

The NR-PDCCH is used to transmit Downlink Control Information (DCI) in adownlink radio communication (radio communication from the base stationapparatus 3 to the terminal apparatus 1). Here, one or more pieces ofDCI (which may be referred to as DCI formats) are defined fortransmission of the downlink control information. In other words, afield for the downlink control information is defined as DCI and ismapped to information bits.

For example, the DCI may be defined to include information forindicating a timing for transmitting HARQ-ACK for a scheduled NR-PDSCH(for example, the number of symbols from the last symbol included in theNR-PDSCH to the symbol for transmission of the HARQ-ACK).

For example, the DCI may be defined to be used for the scheduling of onedownlink radio communication NR-PDSCH in one cell (transmission of onedownlink transport block).

For example, the DCI may be defined to be used for the scheduling of oneuplink radio communication NR-PUSCH in one cell (transmission of oneuplink transport block).

Here, the DCI includes information of the scheduling of the NR-PDSCH orthe NR-PUSCH. Here, the DCI for the downlink is also referred to as adownlink grant or downlink assignment. Here, the DCI for the uplink isalso referred to as an uplink grant or Uplink assignment.

The NR-PDSCH is used to transmit downlink data (Downlink Shared CHannel(DL-SCH)) from Medium Access Control (MAC). The NR-PDSCH is also used totransmit System Information (SI), a Random Access Response (RAR), andthe like.

Here, the base station apparatus 3 and the terminal apparatus 1 exchange(transmit and/or receive) signals with each other in a higher layer. Forexample, the base station apparatus 3 and the terminal apparatus 1 maytransmit and/or receive Radio Resource Control (RRC) signaling (alsoreferred to as a Radio Resource Control message (RRC message) or RadioResource Control information (RRC information)) in the Radio ResourceControl (RRC) layer. The base station apparatus 3 and the terminalapparatus 1 may transmit and/or receive a Medium Access Control (MAC)control element in a MAC layer. Here, the RRC signaling and/or the MACcontrol element is also referred to as higher layer signaling. Thehigher layer herein means a higher layer viewed from the physical layer,and thus, may include one or more layers, such as a MAC layer, an RRClayer, an RLC layer, a PDCP layer, and a NAS layer. For example, thehigher layer in a process of the MAC layer may include one or morelayers such as an RRC layer, an RLC layer, a PDCP layer, and a NASlayer.

The NR-PDSCH may be used to transmit the RRC signaling and the MACcontrol element (Medium Access Control Element (MAC CE)). Here, the RRCsignaling transmitted from the base station apparatus 3 may be signalingcommon to multiple terminal apparatuses 1 in a cell. The RRC signalingtransmitted from the base station apparatus 3 may be signaling dedicatedto a certain terminal apparatus 1 (also referred to as dedicatedsignaling). In other words, terminal apparatus-specific (UE-specific)information may be transmitted through signaling dedicated to thecertain terminal apparatus 1.

The NR-PRACH may be used to transmit a random access preamble. TheNR-PRACH may be used to indicate an initial connection establishmentprocedure, a handover procedure, a connection re-establishmentprocedure, uplink transmission synchronization (timing adjustment), andan NR-PUSCH (UL-SCH) resource request.

In FIG. 1, the following downlink physical signals are used for thedownlink radio communication. Here, the downlink physical signals arenot used to transmit the information output from the higher layers butis used by the physical layer.

-   -   Synchronization signal (SS)    -   Reference Signal (RS)

The synchronization signal is used for the terminal apparatus 1 to takesynchronization in a frequency domain and a time domain in the downlink.The synchronization signal may include a Primary Synchronization Signal(PSS) and a Second Synchronization Signal (SSS). The synchronizationsignal may be used for the terminal apparatus 1 to identify a CellIdentifier (cell ID). The synchronization signal may also be used toselect/identify/determine a base station transmission beam to be used bythe base station apparatus 3 for downlink beamforming, and/or a terminalreception beam to be used by the terminal apparatus 1. In other words,the synchronization signal may be used for the terminal apparatus 1 toselect/identify/determine the index of the base station transmissionbeam applied to the downlink signal by the base station apparatus 3.Here, the synchronization signal, the primary synchronization signal,and the secondary synchronization signal used in NR may be referred toas NR-SS, NR-PSS, and NR-SSS, respectively.

A downlink reference signal (hereinafter, also simply referred to as areference signal in the present embodiment) may be classified intomultiple reference signals, based on applications and the like. Forexample, one or more of the following reference signals may be used forthe reference signal.

-   -   Demodulation Reference Signal (DMRS)    -   Channel State Information Reference Signal (CSI-RS)    -   Phase Tracking Reference Signal (PTRS)    -   Mobility Reference Signal (MRS)

The DMRS may be used for channel compensation in demodulating a receivedmodulated signal. The DMRS for demodulating the NR-PDSCH, the DMRS fordemodulating the NR-PDCCH, and/or the DMRS for demodulating the NR-PBCHmay collectively refer to as the DMRS, or may be individually defined.

The CSI-RS may be used for channel state measurement. The PTRS may beused to track a phase due to movement of the terminal or the like. TheMRS may be used to measure reception quality from multiple base stationapparatuses for handover.

The reference signal for compensating for a phase noise may be definedin the reference signal.

Note that functions of at least some of the multiple reference signalsmay be had by other reference signals.

At least one of the multiple reference signals or other referencesignals may be defined as a Cell-specific reference signal (CRS)individually configured for the cell, a Beam-specific reference signal(BRS) for each transmission beam used by the base station apparatus 3 orthe transmission reception point 4, and/or a UE-specific referencesignal (URS) configured individually for the terminal apparatus 1.

At least one of the reference signals may be used for Finesynchronization of which the level is sufficient to performdetermination of a numerology for a radio parameter or a subcarrierspacing, an FFT window synchronization, or the like.

At least one of the reference signals may be used for Radio ResourceMeasurement (RRM). At least one of the reference signals may be used forbeam management.

A synchronization signal may be used for at least one of the referencesignals.

In FIG. 1, the following uplink physical channels are used for uplinkradio communication between the terminal apparatus 1 and the basestation apparatus 3 (radio communication from the terminal apparatus 1to the base station apparatus 3). The uplink physical channels are usedfor transmitting information output from the higher layers.

-   -   New Radio Physical Uplink Control CHannel (NR-PUCCH)    -   New Radio Physical Uplink Shared CHannel (NR-PUSCH)    -   New Radio Physical Random Access CHannel (NR-PRACH)

The NR-PUCCH is used to transmit Uplink Control Information (UCI). Here,the uplink control information may include Channel State Information(CSI) used to indicate a downlink channel state. The uplink controlinformation may include a Scheduling Request (SR) used to request anUL-SCH resource. The uplink control information may include a HybridAutomatic Repeat request ACKnowledgment (HARQ-ACK). The HARQ-ACK mayindicate a HARQ-ACK for downlink data (Transport block, Medium AccessControl Protocol Data Unit (MAC PDU), or a Downlink-Shared Channel(DL-SCH)).

The NR-PUSCH is used to transmit uplink data (Uplink Shared CHannel(UL-SCH)) from the Medium Access Control (MAC). The NR-PUSCH may be usedto transmit a HARQ-ACK and/or CSI along with the uplink data.Furthermore, the NR-PUSCH may be used to transmit the HARQ-ACK and CSIonly. That is, the NR-PUSCH may be used to transmit UCI only.

The NR-PUSCH may be used to transmit the RRC signaling and the MACcontrol element. Here, the NR-PUSCH may be used to transmit UECapabilities in the uplink.

Note that the same reference name (for example, NR-PCCH) and the samechannel definition may be used for the NR-PDCCH and the NR-PUCCH. Notethat the same reference name (for example, NR-PSCH) and the same channeldefinition may be used for the NR-PDSCH and the NR-PUSCH.

Hereinafter, the subframe will be described. The subframe in the presentembodiment may be also referred to as a resource unit, a radio frame, atime period, or a time interval.

FIG. 2 is a diagram illustrating an example of a schematic configurationof a downlink slot according to the embodiment of the present invention.Each of the radio frames is 10 ms in length. Each of the radio framesincludes 10 subframes and X slots. In other words, the length of onesubframe is 1 ms. For each of the slots, a time length is defineddepending on a subcarrier spacing. For example, in a case that asubcarrier spacing of OFDM symbols is 15 kHz with an NCP (Normal CyclicPrefix), X=7 or X=14, and 0.5 ms and 1 ms, respectively. In a case thatthe subcarrier spacing is 60 kHz, X=7 or X=14, and 0.125 ms and 0.25 ms,respectively. FIG. 2 illustrates a case of X=7 as an example. Note thatalso in a case of X=14, the same expansion can be achieved. The uplinkslot may be defined similarly, and the downlink slot and the uplink slotmay be defined separately.

The signal or the physical channel transmitted in each of the slots isexpressed by a resource grid. The resource grid is defined by multiplesubcarriers and multiple OFDM symbols. The number of subcarriersconstituting one slot depends on cell downlink and uplink bandwidths.Each element within the resource grid is referred to as a resourceelement. The resource element may be identified by a subcarrier numberand an OFDM symbol number.

A resource block is used to express mapping of resource elements for acertain physical downlink channel (such as the PDSCH) or a certainphysical uplink channel (such as the PUSCH). For the resource block, avirtual resource block and a physical resource block are defined. Acertain physical uplink channel is first mapped to a virtual resourceblock. Thereafter, the virtual resource block is mapped to the physicalresource block. In the case that the number X of OFDM symbols includedin a slot is 7 (X=7) with the NCP, one physical resource block isdefined by seven OFDM symbols consecutive in the time domain and by 12subcarriers consecutive in the frequency domain. Specifically, onephysical resource block includes (7×12) resource elements. In a case ofan Extended CP (ECP), one physical resource block is defined by six OFDMsymbols consecutive in the time domain and by 12 subcarriers consecutivein the frequency domain, for example. Specifically, one physicalresource block includes (6×12) resource elements. At this time, onephysical resource block corresponds to one slot in the time domain andcorresponds to 180 kHz in the frequency domain. The physical resourceblocks are numbered from zero in the frequency domain.

Next, the subframe, the slot, and the mini-slot will be described. FIG.3 is a diagram illustrating a relationship between the subframe, theslot, and the mini-slot in the time domain. As illustrated in thedrawing, three time units are defined. The subframe is 1 ms regardlessof the subcarrier spacing, the number of OFDM symbols included in theslot is 7 or 14, and a slot length depends on the subcarrier spacing.Here, in a case that the subcarrier spacing is 15 kHz, 14 OFDM symbolsare included in one subframe. Thus, in a case that the subcarrierspacing is Δf (kHz), the slot length may be defined as 0.5/(Δf/15) ms ina case that the number of OFDM symbols constituting one slot is 7. Here,Δf may be defined by the subcarrier spacing (kHz). In the case that thenumber of OFDM symbols constituting one slot is 7, the slot length maybe defined as 1/(Δf/15) ms. Here, Δf may be defined by the subcarrierspacing (kHz). Furthermore, in a case that the number of OFDM symbolsincluded in the slot is X, the slot length may be defined asX/14/(Δf/15) ms.

The mini-slot (which may be referred to as a sub-slot) is a time unitincluding the OFDM symbols that are less than the number of OFDM symbolsincluded in the slot. The drawing illustrates a case that the mini-slotincludes two OFDM symbols as an example. The OFDM symbol in themini-slot may match an OFDM symbol timing that constitutes the slot.Note that a minimum unit of scheduling may be a slot or a mini-slot.

FIG. 4 illustrates an example of a slot or a subframe. Here, a case thatthe slot length is 0.5 ms in the subcarrier spacing 15 kHz isillustrated as an example. In the drawing, D represents the downlink,and U represents the uplink. As illustrated in the drawing, during acertain time period (for example, the minimum time period to beallocated to one UE in the system), one or more of the followings may beincluded:

-   -   a downlink part (duration),    -   a gap, and    -   a uplink part (duration).

(a) of FIG. 4 is an example in which in a certain time period (which maybe referred to as, for example, a minimum unit of time resource that canbe allocated to one UE, a time unit, or the like, or multiple minimumunits of time resource may be bundled and referred to as a time unit) isentirely used for downlink transmission. (b) of FIG. 4 illustrates anexample in which an uplink is scheduled via a PCCH, for example, byusing the first time resource, through a gap for a processing delay ofthe PCCH, a time for switching from a downlink to an uplink, andgeneration of a transmit signal, and then, an uplink signal istransmitted. (c) of FIG. 4 illustrates an example in which a downlinkPCCH and/or downlink PSCH are transmitted by using the first timeresource, and a PSCH or PCCH is transmitted through a gap for aprocessing delay, a time for switching from a downlink to an uplink, andgeneration of a transmit signal. Here, as an example, the uplink signalmay be used to transmit the HARQ-ACK and/or CSI, namely, the UCI. (d) ofFIG. 4 illustrates an example in which a downlink PCCH and/or downlinkPSCH are transmitted by using the first time resource, and an uplinkPSCH or PCCH is transmitted through a gap for a processing delay, a timefor switching from a downlink to an uplink, and generation of a transmitsignal. Here, as an example, the uplink signal may be used to transmitthe uplink data, namely, the UL-SCH. (e) of FIG. 4 illustrates anexample in which the entire subframe is used for uplink transmission(uplink PSCH or PCCH).

The above-described downlink part and uplink part may include multipleOFDM symbols as is the case in LTE.

The beamforming, the beam management and/or the beam sweeping accordingto the embodiment of the present invention will be described.

The beamforming on the transmission side (that is the base stationapparatus 3 in a case of the downlink, or the terminal apparatus 1 in acase of the uplink) is a method of controlling, in an analogue ordigital manner, an amplitude/phase of a signal for each of multipletransmit antenna elements to transmit the signal with a high transmitantenna gain in any direction, and a field pattern thereof is referredto as a transmission beam. The beamforming on the reception side (thatis the terminal apparatus 1 in a case of the downlink, or the basestation apparatus 3 in a case of the uplink) is a method of controlling,in an analogue or digital manner, an amplitude/phase of a signal foreach of multiple receive antenna elements to receive the signal with ahigh receive antenna gain in any direction, and a field pattern thereofis referred to as a reception beam. The beam management may bedirectivity alignment of the transmission and/or reception beams, andoperations of the base station apparatus 3 and/or the terminal apparatus1 for acquiring a beam gain.

FIG. 5 illustrates an example of the beamforming. Multiple antennaelements are connected to one Transceiver unit (TXRU) 50, and cancontrol phases by phase shifters 51 of the respective antenna elementsand transmit from the antenna elements 52 to direct a beam for thetransmit signals in any direction. Typically, the TXRU 50 may be definedas an antenna port, and only an antenna port may be defined in theterminal apparatus 1. By controlling the phase shifters 51, the basestation apparatus 3 can direct the directivity in any direction, andthus, the base station apparatus 3 can communicate using a beam having ahigh gain with respect to the terminal apparatus 1.

The beamforming may be referred to as virtualization, precoding, andmultiplication with a weight, for example. A signal transmitted throughbeamforming may be simply referred to as a transmission beam.

In the present embodiment, a transmission beam used by the terminalapparatus 1 in beamforming for uplink transmission is referred to as anuplink transmission beam (UL Tx beam), and a reception beam used by thebase station apparatus 3 in beamforming for uplink reception is referredto as an uplink reception beam (UL Rx beam). A transmission beam used bythe base station apparatus 3 in beamforming for downlink transmission isreferred to as a downlink transmission beam (DL Tx beam), and areception beam used by the terminal apparatus 1 in beamforming fordownlink reception is referred to as a downlink reception beam (DL Rxbeam). Note that the uplink transmission beam and the uplink receptionbeam may be collectively referred to as an uplink beam, and the downlinktransmission beam and the downlink reception beam may be collectivelyreferred to as a downlink beam. Note that a process performed by theterminal apparatus 1 for the uplink beamforming may be referred to asuplink transmission beam processing or uplink precoding, and a processperformed by the base station apparatus 3 for the uplink beamforming maybe referred to as uplink reception beam processing. Note that a processperformed by the terminal apparatus 1 for the downlink beamforming maybe referred to as downlink reception beam processing, and a processperformed by the base station apparatus 3 for the downlink beamformingmay be referred to as downlink transmission beam processing or downlinkprecoding.

Note that the base station apparatus 3 may transmit the signal usingmultiple downlink transmission beams in one OFDM symbol. For example,the antenna elements of the base station apparatus 3 may be divided intosubarrays to perform beamforming differently for each of the subarrays.Downlink beamforming may be performed differently for each polarizationusing a polarization antenna. Similarly, the terminal apparatus 1 maytransmit a signal by using multiple uplink transmission beams in oneOFDM symbol.

Note that in the present embodiment, a case is described in which thebase station apparatus 3 switches and uses multiple downlinktransmission beams in a cell constituted by the base station apparatus 3and/or the transmission reception point 4, but a cell may be constitutedindividually for each downlink transmission beam.

The beam management may include the following operations.

-   -   Beam selection    -   Beam refinement    -   Beam recovery

For example, the beam selection may be an operation to select a beam ina communication between the base station apparatus 3 and the terminalapparatus 1. The beam refinement may be an operation to select a beamhaving a further higher gain or change a beam between an optimal basestation apparatus 3 and the terminal apparatus 1 due to movement of theterminal apparatus 1. The beam recovery may be an operation to re-selecta beam in a case that a quality of the communication link decreases dueto a blockage generated by an obstacle, a human passing, or the like ina communication between the base station apparatus 3 and the terminalapparatus 1. The above operations are not limited to the above purposes.The base station apparatus 3 may perform the beam management in avariety of contexts and, therefore, can exert an effect without limitingthe purpose.

For example, a reference signal (for example, CSI-RS) may be used inselecting a transmission beam of the base station apparatus 3 in theterminal apparatus 1, or a Quasi Co-Location (QCL) assumption may beused.

In a case that a Long Term Property of a channel on which a symbol iscarried at an antenna port can be estimated from a channel on which asymbol is carried at another antenna port, the two antenna ports aresaid to be in QCL. The long term property of the channel includes one ormore of a delay spread, a Doppler spread, a Doppler shift, an averagegain, and an average delay. For example, in a case that antenna port 1and antenna port 2 are in QCL for an average delay, it means that areception timing of antenna port 2 may be inferred from a receptiontiming of antenna port 1.

The QCL may also be expanded to the beam management. Therefore, aspatially expanded QCL may be newly defined. For example, one or more ofthe following may be further included in addition to the above as theLong term property of the channel in the QCL assumption for the space.

-   -   Arrival angle in a radio link or a channel (such as Angle of        Arrival (AoA) and Zenith angle of Arrival (ZoA)) and/or its        Angle Spread (such as Angle Spread of Arrival (ASA) and Zenith        angle Spread of Arrival (ZSA)),    -   Departure angle in a radio link or a channel (such as AoD and        ZoD) and/or its Angle Spread (such as Angle Spread of Departure        (ASD) and Zenith angle Spread of Departure (ZSS)), and    -   Spatial Correlation.

According to this method, as the beam management, the operation of thebase station apparatus 3 and the terminal apparatus 1 equivalent to thebeam management may be defined by the QCL assumption of the space andthe radio resource (time and/or frequency).

Note that an antenna port may be assigned to each of the precoding orthe transmission beams. For example, a signal to be transmitted by usinga different precoding or a signal to be transmitted by using a differenttransmission beam according to the present embodiment may be defined asa signal to be transmitted through one or more different antenna ports.Note that the antenna port is defined as an antenna port that allows achannel on which a certain symbol is transmitted through a certainantenna port to be inferred from a channel on which another symbol istransmitted through the same antenna port. The same antenna port alsomeans that the antenna port number (the number for identifying anantenna port) may be the same. An antenna port set may be constituted bymultiple antenna ports. The same antenna port set also means that theantenna port set number (the number for identifying an antenna port set)may be the same. A signal to be transmitted by applying a differentterminal transmission beam also means that the signal may be transmittedthrough a different antenna port or a different antenna port setconstituted by multiple antenna ports. A beam index may be an OFDMsymbol number, an antenna port number, or an antenna port set number.

A complex modulation symbol for one or more layers generated by layermapping is input into transform precoding. The transform precoding maybe a process for dividing a block of complex-valued symbols into setsfor each layer corresponding to one OFDM symbol. In a case that the OFDMis used, a process of Discrete Fourier Transform (DFT) in the transformprecoding may not be necessary. In the precoding, the block of vectorsobtained from a transform precoder may be input to generate a block ofvectors to be mapped to a resource element. In a case of spatialmultiplexing, one of precoding matrices may be adapted in generating theblock of vectors to be mapped to a resource element. This process may bereferred to as digital beamforming. Further, the precoding may bedefined to include analog beamforming and digital beamforming, or may bedefined as digital beamforming. The beamforming may be applied to aprecoded signal, and the precoding may be applied to a signal to whichthe beamforming is applied. The beamforming may include digitalbeamforming and may not include analog beamforming, or may include bothdigital beamforming and analog beamforming. A beamformed signal, aprecoded signal, or a beamformed and precoded signal may be referred toas a beam. An index of a beam may be a precoding matrix index. The beamindex and the precoding matrix index may be defined independently. Theprecoding matrix indicated by the precoding matrix index may be appliedto the beam indicated by the beam index to generate a signal. Thebeamforming indicated by the beam index may be applied to the signal towhich the precoding matrix indicated by the precoding matrix index isapplied, to generate a signal. The digital beamforming may includedifferent precoding matrix adaptation to a resource in a frequencydirection (for example, a set of subcarriers).

Note that, in the present embodiment, a radio link constituted by usinga prescribed transmission beam and/or a prescribed reception beam may bereferred to as a beam pair link. For example, in the downlink, a beampair link constituted by using different downlink transmission beamsand/or different downlink reception beams may be a different downlinkbeam pair link. For example, in the uplink, a beam pair link constitutedby using different uplink transmission beams and/or different uplinkreception beams may be a different uplink beam pair link. For example, astate in which the terminal apparatus 1 may receive downlink signals byusing multiple downlink transmission beams and/or multiple downlinkreception beams in a certain cell may be referred to as a state havingmultiple downlink beam pair links. For example, a state in which theterminal apparatus 1 may transmit the uplink signals by using multipleuplink transmission beams and/or multiple uplink reception beams in acertain cell may be referred to as a state having multiple uplink beampair links.

A concept of the downlink beam pair link according to the presentembodiment will be described.

FIG. 6 illustrates a case where the terminal apparatus 1 and the basestation apparatus 3 form multiple downlink beam pair links in the cell100. As a first downlink beam pair link, a downlink signal transmittedby the base station apparatus 3 by using a downlink transmission beam t1is received by the terminal apparatus 1 by using a downlink receptionbeam r1. As a second downlink beam pair link, a downlink signaltransmitted by the base station apparatus 3 by using a downlinktransmission beam t2 is received by the terminal apparatus 1 by using adownlink reception beam r2. As a third downlink beam pair link, adownlink signal transmitted by the base station apparatus 3 by using adownlink transmission beam t3 is received by the terminal apparatus 1 byusing a downlink reception beam r3. In this case, three downlink beampair links are formed between the terminal apparatus 1 and the basestation apparatus 3, and downlink transmission and/or reception isperformed in all or some of three downlink beam pair links. For example,the terminal apparatus 1 measures a received power and/or a receptionquality by way of a reference signal in each downlink beam pair link.

Note that multiple downlink beam pair links may be formed for onedownlink transmission beam by using multiple downlink reception beams.Note that multiple downlink beam pair links may be formed for onedownlink reception beam by using multiple downlink transmission beams.Note also that regardless of the downlink reception beam to be used, onedownlink beam pair link may be associated with one downlink transmissionbeam. In addition, note that regardless of the uplink transmission beamto be used, one uplink beam pair link may be associated with one uplinkreception beam.

A concept of a downlink radio link (which may be simply referred to as aradio link) in the present embodiment will be described.

In the present embodiment, only one downlink radio link may be formedfor each serving cell. The downlink radio link may refer to a downlinkradio link associated with a serving cell independently of a downlinkbeam pair link associated with the beam. Note that the downlink radiolink may be one of multiple downlink beam pair links formed for acertain terminal apparatus 1 in the serving cell. Note that the downlinkradio link may be associated with two or more of multiple downlink beampair links formed for the certain terminal apparatus 1 in the servingcell. For example, the terminal apparatus 1 may measure multiplereceived powers and/or reception qualities by way of multiple referencesignals in one downlink radio link.

Monitoring of the NR-PDCCH according to the present embodiment will bedescribed.

FIG. 7 is a flowchart illustrating an example of transmitting a downlinkcontrol channel in the base station apparatus 3 according to the presentembodiment. The base station apparatus 3 generates multiple referencesignals to be transmitted to the terminal apparatus (S1001). The basestation apparatus 3 transmits a signal including first informationindicating a resource of each of multiple downlink control channelregions (which may be referred to as search space, for example)associated with each of the multiple reference signals (S1002). Notethat the signal including the first information may be an RRC message.The base station apparatus 3 transmits a signal including secondinformation indicating one or more of the multiple downlink controlchannel regions (S1003). Note that the signal including the secondinformation may be a MAC CE. The base station apparatus 3 transmits thedownlink control channel on the resource of the downlink control channelregion based on the first information and the second information(S1004).

FIG. 8 is a flowchart illustrating an example of monitoring a downlinkcontrol channel in the terminal apparatus 1 according to the presentembodiment. The terminal apparatus 1 receives a signal including firstinformation indicating a resource of each of multiple downlink controlchannel regions (which may be referred to as search space, for example)associated with each of the multiple reference signals (S2001). Theterminal apparatus 1 receives a signal including second informationconfiguring one or more of the multiple downlink control channel regions(S2002). The terminal apparatus 1 monitors the downlink control channelfor decoding on a resource in the downlink control channel region basedon the first information and the second information (S2003).

Note that an RRC layer for the base station apparatus 3 may transmit, tothe terminal apparatus 1, an RRC message including an index indicating aparameter configuring one or more search space candidates and each ofone or more search space candidates. Note that the terminal apparatus 1may receive, from an RRC layer for the base station apparatus 3, an RRCmessage including an index indicating a parameter configuring one ormore search space candidates and each of one or more search spacecandidates. Each search space candidate may be configured withparameters such as time, frequency, and/or QCL. Each search spacecandidate may be associated with one or more reference signals (forexample, non-zero power CSI-RS, or the like), based on information suchas QCL. Note that each search space candidate may be configured withparameters such as time, frequency, and/or QCL. Each search spacecandidate may be associated with one or more reference signals (forexample, non-zero power CSI-RS, or the like), based on information suchas QCL. Note that each search space candidate may associated with eachbeam pair link. The terminal apparatus 1 that has received the RRCmessage for configuring one or more search space candidates may activateone or more search spaces to monitor the NR-PDCCH in response toreceiving the information for identifying one or more search spaces tomonitor the NR-PDCCH.

Note that the MAC layer for the base station apparatus 3 may determineone or more search spaces for the terminal apparatus 1 to monitor theNR-PDCCH, and may notify the terminal apparatus 1 of the information foridentifying one or more search spaces to monitor the NR-PDCCH. Note thatthe MAC entity for the terminal apparatus 1 may receive the informationfor identifying search spaces of one or more NR-PDCCHs for the terminalapparatus 1 to monitor, from the MAC layer of the base station apparatus3. The information for identifying search spaces of one or moreNR-PDCCHs to monitor may be transmitted in the MAC control element. Theterminal apparatus 1 may activate one or more NR-PDCCH search spaces tobe monitored in response to receiving the information for identifyingsearch spaces of one or more NR-PDCCHs to monitor.

Note that one or more search spaces for the terminal apparatus 1 tomonitor the NR-PDCCH may be indicated by bit map information in which abit is associated with each of indices of the multiple search spacecandidates notified by the RRC layer for the base station apparatus 3.This bitmap information may cause the terminal apparatus 1 to monitorthe activated search space.

Beam pair link monitoring by the terminal apparatus 1 will be describedbelow. Hereinafter, a description is made referring a downlink beam pairlink simply as a beam pair link, and a similar method may be applied toan uplink beam pair link.

The terminal apparatus 1 according to the present embodiment monitors aquality of one or more beam pair links (which may be referred to as abeam pair link quality or a downlink beam pair link quality, forexample). Note that one or more beam pair links of which the quality theterminal apparatus 1 monitors may be beam pair links on which theterminal apparatus 1 monitors the NR-PDCCH transmitted from the basestation apparatus 3. Note that the terminal apparatus 1 may monitor oneor more beam pair links in the primary cell, one or more beam pair linksin the primary secondary cell, and/or one or more beam pair links in thesecondary cell. Note that one or more beam pair links of which thequality the terminal apparatus 1 monitors may be indicated by theterminal apparatus 1 from the base station apparatus 3 base stationapparatus 3 by using the MAC CE, the RRC, and/or the DCI. The terminalapparatus 1 may monitor one or more beam pair links corresponding to therespective search spaces, based on that one or more search spaces tomonitor the NR-PDCCH are configured (or activated).

The terminal apparatus 1 monitors, in order to detect a beam pair linkquality of a beam pair link, the beam pair link quality, based onreference signals corresponding to the beam pair link.

Note that the reference signal for monitoring a beam pair link qualityof a beam pair link may be a reference signal for decoding the NR-PDCCHcorresponding to that beam pair link.

Note that the reference signal for monitoring a beam pair link qualityof a beam pair link may be CSI-RS (for example, non-zero power CSI-RS,or the like) associated with the beam pair link. For example, the CSI-RSfor monitoring a beam pair link quality of a beam pair link may be aCSI-RS to which a transmission beam corresponding to the beam pair linkis applied.

The terminal apparatus 1 evaluates a certain beam pair link quality at aprescribed timing (for example, every radio frame) over the previoustime period.

Note that the beam pair link quality of the certain beam pair linkevaluated by the terminal apparatus 1 may be a value in a case of usingthe reception beam having the highest quality among one or morereception beams which the terminal apparatus 1 can apply to a downlinktransmission beam used by the base station apparatus 3 in thecorresponding beam pair link.

The terminal apparatus 1 may compare one evaluated beam pair linkquality to one or more thresholds to perform assessment. Such one ormore thresholds may be included in the parameters configuring thecorresponding search space candidate.

The physical layer for the terminal apparatus 1 may determine that themonitored beam pair link is “beam out-of-sync” in a case that the beampair link quality over the previous time period is worse than athreshold value Q₁. The physical layer for the terminal apparatus 1 maysend an indication of “beam out-of-sync” of the monitored beam pair linkto the higher layer, in the case that the beam pair link quality overthe previous time period is worse than the threshold value Q₁.

The physical layer for the terminal apparatus 1 may change the receptionbeam of the monitored beam pair link in the case that the beam pair linkquality over the previous time period is worse than the threshold valueQ₁. The physical layer for the terminal apparatus 1 may determine thatthe monitored beam pair link is “beam out-of-sync” in a case that thebeam pair link quality over the previous time period is worse than thethreshold value Q₁ even in a case that the terminal apparatus 1 uses anyof one or more reception beams which the terminal apparatus 1 can apply.The physical layer for the terminal apparatus 1 may send an indicationof “beam out-of-sync” of the monitored beam pair link to the higherlayer in the case that the beam pair link quality over the previous timeperiod is worse than the threshold value Q₁ even in a case that theterminal apparatus 1 uses any of one or more reception beams which theterminal apparatus 1 can apply.

The physical layer for the terminal apparatus 1 may determine that themonitored beam pair link is “beam in-sync” in a case that the beam pairlink quality over the previous time period is better than a thresholdvalue Q₂. The physical layer for the terminal apparatus 1 may send anindication “beam in-sync” of the monitored beam pair link to the higherlayer, in a case that the beam pair link quality over the previous timeperiod is better than the threshold value Q₂.

The terminal apparatus 1 may compare multiple evaluated beam pair linkqualities to one or more thresholds to perform assessment. Such one ormore thresholds may be included in the parameters configuring thecorresponding search space candidate.

The physical layer for the terminal apparatus 1 may determine “beamout-of-sync” in a case that a prescribed number of beam pair links amongthe multiple beam pair links are worse than the threshold value Q₁ overthe previous time period. The physical layer for the terminal apparatus1 may send an indication “beam out-of-sync” to the higher layer in thecase that a prescribed number of beam pair links among the multiple beampair links are worse than the threshold value Q₁ over the previous timeperiod.

The physical layer for the terminal apparatus 1 may determine “beamin-sync” in a case that a prescribed number of beam pair links among themultiple beam pair links are better than the threshold value Q₂ over theprevious time period. The physical layer for the terminal apparatus 1may send an indication of “beam in-sync” to the higher layer in the casethat a prescribed number of beam pair links among the multiple beam pairlinks are better than the threshold value Q₂ over the previous timeperiod.

Note that the threshold Q₁ may be a value indicating a level at which anNR-PDCCH transmission cannot be securely received (for example, theNR-PDCCH cannot be received at block error rate of 10% or less). Notethat the threshold Q₂ may be a value indicating a level at which anNR-PDCCH transmission can be sufficiently securely received (forexample, the NR-PDCCH can be received at block error rate of 2% orless).

Note that the physical layer for the terminal apparatus 1 may sendvalues for the beam pair links over the previous time period to thehigher layer. Note that the value for the beam pair link quality overthe past period may be the received power of the reference signalreceived in the corresponding beam pair link (referred to as ReferenceSignal Received Power (RSRP), L1-RSRP, and the like).

Hereinafter, an operation related to a Beam Pair Link Failure (BPLF) bythe terminal apparatus 1 will be described.

The RRC layer for the terminal apparatus 1 according to the presentembodiment may perform operations as described below.

In a case that the RRC layer for the terminal apparatus 1 receives N₁continuous indications “beam out-of-sync” from the lower layer, the RRClayer may consider that a beam pair link failure has been detected inone or more beam pair links for monitoring the NR-PDCCH (which may bereferred to as NR-PDCCH monitoring set).

In a case that, among one or more beam pair links for monitoring theNR-PDCCH, the number of beam pair links for which N₁ or more continuousindications “beam out-of-sync” have been received from the lower layeris equal to or more than a certain number at a certain timing, the RRClayer for the terminal apparatus 1 may consider that a beam pair linkfailure has been detected in one or more beam pair links for monitoringthe NR-PDCCH.

In a case that the RRC layer for the terminal apparatus 1 receives N₁continuous indications “beam out-of-sync” from the lower layer, the RRClayer may start a first timer. In a case that the RRC layer for theterminal apparatus 1 receives N₂ continuous indications “beam in-sync”from the lower layer, the RRC layer may stop the first timer.

In a case that, among one or more beam pair links for monitoring theNR-PDCCH, the number of beam pair links for which N₁ or more continuousindications “beam out-of-sync” have been received from the lower layeris equal to or more than a certain number at a certain timing, the RRClayer for the terminal apparatus 1 may start the first timer. In a casethat, among one or more beam pair links for monitoring the NR-PDCCH, thenumber of beam pair links for which N₂ or more continuous indications“beam in-sync” have been received from the lower layer is equal to ormore than a certain number at a certain timing, the RRC layer for theterminal apparatus 1 may stop the first timer.

In a case that the first timer expires (expiry), the RRC layer for theterminal apparatus 1 may consider that a beam pair link failure isdetected in one or more beam pair links for monitoring the NR-PDCCH(which may be referred to as NR-PDCCH monitoring set).

In a case that the RRC layer for the terminal apparatus 1 receives N₃ ormore continuous indications “beam out-of-sync” from the lower layer at acertain timing for all of one or more beam pair links for monitoring theNR-PDCCH, the RRC layer may start a second timer. In a case that, amongone or more beam pair links for monitoring the NR-PDCCH, the number ofbeam pair links for which N₄ or more continuous indications “beamin-sync” have been received from the lower layer is equal to or morethan a certain number at a certain timing, the RRC layer for theterminal apparatus 1 may start the second timer. In a case that thesecond timer expires (expiry), the RRC layer for the terminal apparatus1 may consider that a radio link failure has been detected in one ormore beam pair links for monitoring the NR-PDCCH.

The MAC layer for the terminal apparatus 1 according to the presentembodiment may perform operations as described below.

In a case that the MAC layer for the terminal apparatus 1 receives N₁continuous indications “beam out-of-sync” from the lower layer, the MAClayer may consider that a beam pair link failure has been detected inone or more beam pair links for monitoring the NR-PDCCH (which may bereferred to as NR-PDCCH monitoring set). In a case that the MAC layerfor the terminal apparatus 1 receives N₁ continuous indications “beamout-of-sync” from the lower layer, the MAC layer may generate a MAC CEfor beam recovery.

In a case that, among one or more beam pair links for monitoring theNR-PDCCH, the number of beam pair links for which N₁ or more continuousindications “beam out-of-sync” have been received from the lower layeris equal to or more than a certain number at a certain timing, the MAClayer for the terminal apparatus 1 may consider that a beam pair linkfailure has been detected in one or more beam pair links for monitoringthe NR-PDCCH. In a case that, among one or more beam pair links formonitoring the NR-PDCCH, the number of beam pair links for which N₁ ormore continuous indications “beam out-of-sync” have been received fromthe lower layer is equal to or more than a certain number at a certaintiming, the MAC layer for the terminal apparatus 1 may generate a MAC CEfor beam recovery.

In a case that the MAC layer for the terminal apparatus 1 receives N₁continuous indications “beam out-of-sync” from the lower layer, the MAClayer may start a first timer. In a case that the MAC layer for theterminal apparatus 1 receives N₂ continuous indications “beam in-sync”from the lower layer, the MAC layer may stop the first timer.

In a case that, among one or more beam pair links for monitoring theNR-PDCCH, the number of beam pair links for which N₁ or more continuousindications “beam out-of-sync” have been received from the lower layeris equal to or more than a certain number at a certain timing, the MAClayer for the terminal apparatus 1 may start the first timer. In a casethat, among one or more beam pair links for monitoring the NR-PDCCH, thenumber of beam pair links for which N₂ continuous indications “beamin-sync” have been received from the lower layer is equal to or morethan a certain number at a certain timing, the MAC layer for theterminal apparatus 1 may stop the first timer.

In a case that the first timer expires (expiry), the MAC layer for theterminal apparatus 1 may consider that a beam pair link failure isdetected in one or more beam pair links for monitoring the NR-PDCCH(which may be referred to as NR-PDCCH monitoring set). In the case thatthe first timer expires (expiry), the MAC layer for the terminalapparatus 1 may generate a MAC CE for beam recovery.

The MAC layer for the terminal apparatus 1 receives a value for a beampair link quality over the previous time period corresponding to each ofone or more beam pair links, and in a case that the values for the beampair link qualities of a certain number or more of beam pair links areworse than a threshold value Q₃ at a certain timing, the MAC layer maydetermine “beam out-of-sync”. The MAC layer for the terminal apparatus 1receives a value for a beam pair link quality over the previous timeperiod corresponding to each of one or more beam pair links, and in acase that the values for the beam pair link qualities of a certainnumber or more of beam pair links are better than a threshold value Q₄at a certain timing, the MAC layer may determine “beam in-sync”. The MAClayer for the terminal apparatus 1 receives a value for a beam pair linkquality over the previous time period corresponding to each of one ormore beam pair links, and in a case that the values for the beam pairlink qualities of a certain number or more of beam pair links are worsethan a threshold value Q₃ at a certain timing or multiple continuoustimings, the MAC layer may start a first timer. The MAC layer for theterminal apparatus 1 receives a value for a beam pair link quality overthe previous time period corresponding to each of one or more beam pairlinks, and in a case that the values for the beam pair link qualities ofa certain number or more of beam pair links are better than a thresholdvalue Q₄ at a certain timing or multiple continuous timings, the MAClayer may stop the first timer. The MAC layer for the terminal apparatus1 receives a value for a beam pair link quality over the previous timeperiod corresponding to each of one or more beam pair links, and in acase that the values for the beam pair link qualities of a certainnumber or more of beam pair links are worse than a threshold value Q₃ ata certain timing or multiple continuous timings, the MAC layer generatea MAC CE for beam recovery. Such one or more thresholds may be includedin the parameters configuring the corresponding search space candidate.

Note that the MAC layer for the terminal apparatus 1 may perform afiltering process on the value for the beam pair link quality receivedfrom the lower layer. In a case that, among the filtering-processedvalues (also referred to as L2-filtered-RSRP) for the beam pair linkqualities corresponding to one or more beam pair links, a certain numberor more of values are worse than a threshold Q₅ at a certain timing, theMAC layer for the terminal apparatus 1 may determine “beam out-of-sync”.In a case that, among the filtering-processed values for the beam pairlink qualities corresponding to one or more beam pair links, a certainnumber or more of values are better than a threshold Q₆ at a certaintiming, the MAC layer for the terminal apparatus 1 may determine “beamin-sync”. In a case that, among the filtering-processed values for thebeam pair link qualities corresponding to one or more beam pair links, acertain number or more of values are worse than the threshold Q₅ at acertain timing or multiple continuous timings, the MAC layer for theterminal apparatus 1 may start a first timer. In a case that, among thefiltering-processed values for the beam pair link qualitiescorresponding to one or more beam pair links, a certain number or moreof values are better than the threshold Q₆ at a certain timing ormultiple continuous timings, the MAC layer for the terminal apparatus 1may stop a first timer. In a case that, among the filtering-processedvalues for the beam pair link qualities corresponding to one or morebeam pair links, a certain number or more of values are worse than thethreshold Q₅ at a certain timing or multiple continuous timings, the MAClayer for the terminal apparatus 1 may generate a MAC CE for beamrecovery. Such one or more thresholds may be included in the parametersconfiguring the corresponding search space candidate.

The terminal apparatus 1 according to the present embodiment may triggera beam pair link status reporting to the base station apparatus 3 in acase of a prescribed condition in the MAC layer and/or the RRC layer(for example, in a case that a beam pair link failure is detected).

FIG. 9 is a flowchart illustrating an example of triggering the beampair link status reporting in the terminal apparatus 1 according to thepresent embodiment. The terminal apparatus 1 configures multiple beampair links for monitoring the downlink control channel (S3001). Theterminal apparatus 1 after configuring multiple beam pair links formonitoring the downlink control channel monitors a quality of each ofthe multiple beam pair links (S3002). In a case that, among multiplebeam pair links of which the qualities are monitored, the qualities of aprescribed number of beam pair links decrease and a beam pair linkfailure is detected, the terminal apparatus 1 triggers a beam pair linkstatus reporting (S3003). The triggered beam pair link status reportingis cancelled in a case that a prescribed condition is met (S3004).

Note that an uplink resource used for reporting a beam pair link statusmay be a physical uplink shared channel (PUSCH) allocated from the basestation apparatus 3.

In a case that the terminal apparatus 1 determines that the beam pairlink status reporting has been triggered and is not canceled, theterminal apparatus 1 may perform the following procedures.

-   -   In a case that the MAC entity for the terminal apparatus 1 has        an uplink resource for a new transmission, the terminal        apparatus 1 may generate a MAC CE for the beam pair link status        reporting. Note that the terminal apparatus 1 that has generated        the MAC CE for the beam pair link status reporting may start or        restart a timer for retransmission.    -   In a case that the MAC entity for the terminal apparatus 1 does        not have the uplink resource for a new transmission and an        uplink grant is not configured, the terminal apparatus 1 may        trigger a beam recovery request.

The terminal apparatus 1 may cancel the triggered beam pair link statusreporting in a case that the quality of the beam pair link for themonitored NR-PDCCH has been improved.

The terminal apparatus 1 may cancel the triggered beam pair link statusreporting in a case that the beam pair link status report is included ina MAC PDU to be transmitted.

Note that there may be at most one beam pair link status report that MACentities transmit at a Transmission Time Interval (TTI) at most.

The terminal apparatus 1 according to the present embodiment may triggera beam recovery request to the base station apparatus 3 in a case of aprescribed condition in the MAC layer and/or the RRC layer. For example,the terminal apparatus 1 may trigger a beam recovery request in a casethat a beam pair link failure is detected. For example, the terminalapparatus 1 may trigger the beam recovery request in a case that thebeam pair link status reporting is triggered and the terminal apparatus1 does not have an uplink resource for beam pair link status reporting.

FIG. 10 is a flowchart illustrating an example of triggering a beamrecovery request in the terminal apparatus 1 according to the presentembodiment. The terminal apparatus 1 configures multiple beam pair linksfor monitoring the downlink control channel (S4001). The terminalapparatus 1 after configuring multiple beam pair links for monitoringthe downlink control channel monitors a quality of each of the multiplebeam pair links (S4002). In a case that, among multiple beam pair linksof which the qualities are monitored, the qualities of a prescribednumber of beam pair links decrease and a beam pair link failure isdetected, the terminal apparatus 1 triggers a beam recovery request(S4003). The triggered beam recovery request is cancelled in a case thata prescribed condition is met (S4004).

Note that the triggered beam recovery request may be treated as in apending state until canceled.

Note that the beam recovery request in the pending state may be canceledin a case that the terminal apparatus 1 receives a new configuration ofthe beam pair link for monitoring the NR-PDCCH.

Note that the beam recovery request in the pending state may becancelled in a case that a MAC PDU is assembled and the PDU includes thebeam pair link status report.

Note that the beam recovery request in the pending state may be canceledin a case that the terminal apparatus 1 detects the NR-PDCCH in aprescribed search space.

Note that the beam recovery request may be used for the terminalapparatus 1 to request a new configuration of the beam pair link formonitoring the NR-PDCCH to the base station apparatus 3.

Note that the beam recovery request may be used for the terminalapparatus 1 to request an uplink resource for beam pair link statusreporting to the base station apparatus 3.

Note that the beam recovery request may be used for the terminalapparatus 1 to indicate information associated with one or more ofmultiple downlink transmission beams available to the base stationapparatus 3.

The terminal apparatus 1 may set a beam recovery request counter to zeroin a case that the terminal apparatus 1 triggers the beam recoveryrequest.

The terminal apparatus 1 may initiate a random access procedure in acase that the beam recovery request is pending and the terminalapparatus 1 does not have the uplink resource valid for the beamrecovery request in any TTI.

The terminal apparatus 1 may perform the following process in a casethat the beam recovery request is pending and the terminal apparatus 1has the uplink resource valid for the beam recovery request in a certainTTI.

-   -   The terminal apparatus 1 may increment the beam recovery request        counter in a case that the beam recovery request counter is less        than the upper limit value of the beam recovery request counter.    -   The terminal apparatus 1 may indicate signaling the beam        recovery request using the uplink resource for the beam recovery        request to the physical layer in a case that the beam recovery        request counter is less than the upper limit value of the beam        recovery request counter.    -   The terminal apparatus 1 may start a beam recovery request        prohibition timer in a case that the beam recovery request        counter is less than the upper limit value of the beam recovery        request counter.    -   The terminal apparatus 1 may cancel the pending beam recovery        request in a case that the beam recovery request counter is        equal to the upper limit value of the beam recovery request        counter (the case of being greater than the upper limit value        may be included).    -   The terminal apparatus 1 may initiate the random access        procedure in a case that the beam recovery request counter is        equal to the upper limit value of the beam recovery request        counter (the case of being greater than the upper limit value        may be included).

Note that in a case that the beam recovery request prohibition timer isrunning, the terminal apparatus 1 may not increment the beam recoveryrequest counter, signal the beam recovery request, and/or initiate thebeam recovery request prohibition timer.

The uplink resource used for the beam recovery request may be an uplinkresource associated with one or more of one or more reference signalsreceived by the terminal apparatus 1.

The uplink resource used for the beam recovery request may be an uplinkresource associated with the beam pair link of which the best beam pairlink quality is the best among one or more beam pair links on which theterminal apparatus 1 monitors the NR-PDCCH.

The uplink resource used for the beam recovery request may be an uplinkresource associated with a reference signal with the best received power(for example, RSRP) among one or more reference signals received by theterminal apparatus 1.

Note that the beam recovery request may be a scheduling request using aprescribed uplink resource. For example, the beam recovery request maybe a scheduling request transmitted using the uplink resource associatedwith one or more of one or more reference signals received by theterminal apparatus 1.

The terminal apparatus 1 that has performed the beam recovery request onthe base station apparatus 3 may monitor a response to the beam recoveryrequest from the base station apparatus 3 in a prescribed period.

The base station apparatus 3 that has received the beam recovery requestfrom the terminal apparatus 1 may transmit a response to the beamrecovery request to the terminal apparatus 1.

The base station apparatus 3 that has received the beam recovery requestfrom the terminal apparatus 1 may select a downlink transmission beamfor transmitting a downlink control channel to the terminal apparatus 1,based on the uplink resource used for the beam recovery request.

Note that the response to the beam recovery request transmitted by thebase station apparatus 3 may be a configuration notification indicatingone or more search spaces for the terminal apparatus 1 to monitor theNR-PDCCH. Note that the configuration indicating one or more searchspaces for the terminal apparatus 1 to monitor the NR-PDCCH may be aconfiguration indicating one or more of multiple search space candidatesconfigured in the RRC layer. Note that one or more search spaces for theterminal apparatus 1 to monitor the NR-PDCCH may be indicated by bit mapinformation in which a bit is associated with each of multiple searchspace candidates. The terminal apparatus 1 that has performed the beamrecovery request may update one or more search spaces to monitor theNR-PDCCH, based on the response to the beam recovery request receivedfrom the base station apparatus 3. Note that the terminal apparatus 1that has performed the beam recovery request may change a downlinkreception beam (which may be a downlink beam pair link) for monitoringone or more NR-PDCCHs, based on the response to the beam recoveryrequest received from the base station apparatus 3.

The base station apparatus 3 that has received the beam recovery requestfrom the terminal apparatus 1 may transmit, to the terminal apparatus 1,an NR-PDCCH including an uplink grant for the terminal apparatus 1 totransmit a downlink beam pair link status report.

The terminal apparatus 1 that has detected the NR-PDCCH including theuplink grant for transmitting the downlink beam pair link status reportmay perform the beam pair link status reporting using the uplinkresource indicated by the uplink grant.

Note that the beam pair link status report transmitted by the terminalapparatus 1 may be a report of the received power of each of one or morereference signals transmitted from the base station apparatus 3. Notethat the received power of each of one or more reference signals may bea received power in a case that a reception beam having the highestpower is used among multiple reception beams which the terminalapparatus 1 can apply in receiving each of the reference signals.

Note that the beam pair link status report transmitted by the terminalapparatus 1 may be index information indicating one or more of one ormore reference signals transmitted from the base station apparatus 3.The terminal apparatus 1 may generate the index information, based onthe received power of the received one or more reference signals.

The terminal apparatus 1 performing the beam pair link status reportingmay generate the MAC CE for the beam pair link status reporting in theMAC layer. The MAC CE for the beam pair link status reporting mayinclude one or more pieces of index information associated with one ormore reference signals.

After performing the beam pair link status reporting, the terminalapparatus 1 that was unable to detect a response to the beam pair linkstatus report in a prescribed period may again perform the beam pairlink status reporting.

The terminal apparatus 1 may consider that the beam pair link statusreporting has failed and proceed to the random access procedure in acase that the terminal apparatus 1 cannot detect the response to thebeam pair link status report even in a case that the beam pair linkstatus reporting has been performed a prescribed number of times (whichmay be one time). The terminal apparatus 1 after proceeding to therandom access procedure detects one or more synchronization signals, andtransmits a random access preamble using a random access resourceassociated with one of the detected one or more synchronization signals.

The search space in the present embodiment may be rephrased into aphysical downlink control channel region. In this case, one or moresearch spaces may be present in the physical downlink control channelregion.

FIGS. 11A to 11C are conceptual diagrams illustrating examples of a casethat a downlink control channel region monitored by the terminalapparatus 1 is changed in the present embodiment.

In FIG. 11A, the base station apparatus 3 transmits reference signals tothe terminal apparatus 1 by using five transmission beams b1, b2, b3,b4, and b5. The terminal apparatus 1 monitors each of the referencesignals transmitted by the five transmission beams, and reports thereceived power and/or reception quality based on the respectivereception characteristics to the base station apparatus 3. The terminalapparatus 1 monitors the NR-PDCCH in the downlink control channel regionassociated with beam pair links m1, m2, and m3 (which may be aconfiguration using the index of the reference signal, the index of thetransmission beam, or the like) configured by the base station apparatus3. Note that the beam pair links m1, m2, and m3 may be associated withthe transmission beam b1, b2, and b3, respectively. The terminalapparatus 1 monitors a quality of each of the configured beam pair linksm1, m2, and m3.

In FIG. 11B, in a case that some of the qualities of the beam pair linksm1, m2, and m3 monitored by the terminal apparatus 1 are worse than athreshold value, the terminal apparatus 1 considers a beam pair linkfailure. In a case that a beam pair link failure occurs, the terminalapparatus 1 transmits a beam recovery request and/or a beam pair linkstatus report to the base station apparatus 3.

In FIG. 11C, the base station apparatus 3 that has received the beamrecovery request and/or the beam pair link status report from theterminal apparatus 1 notifies, to the terminal apparatus 1, that thedownlink control channel region for the terminal apparatus 1 to monitorthe NR-PDCCH is to be a downlink control channel region associated withthe beam pair links m3, m4, and m5. Note that the beam pair links m3,m4, and m5 may be associated with the transmission beams b3, b4, and b5,respectively.

As illustrated in FIGS. 11A to 11C, the base station apparatus 3according to the present embodiment may notify the terminal apparatus 1of the configuration information that the NR-PDCCH is to be monitored ina downlink control channel region associated with one or more ofmultiple reference signals (which may be beams or transmission beams) ofwhich the reception characteristics the terminal apparatus 1 monitors.

Note that a link or reference signal associated with the NR-PDCCH may bereferred to as a serving beam group. A serving beam group activated bythe MAC may be referred to as an activated serving beam group. Asanother example, activated PDCCH and reference signals or links may bereferred to as a serving beam group.

Hereinafter, configurations of apparatuses according to the presentembodiment will be described.

FIG. 12 is a schematic block diagram illustrating a configuration of theterminal apparatus 1 according to the present embodiment. Asillustrated, the terminal apparatus 1 includes a radio transmissionand/or reception unit 10 and a higher layer processing unit 14. Theradio transmission and/or reception unit 10 includes an antenna unit 11,a Radio Frequency (RF) unit 12, and a baseband unit 13. The higher layerprocessing unit 14 includes a medium access control layer processingunit 15 and a radio resource control layer processing unit 16. The radiotransmission and/or reception unit 10 is also referred to as atransmitter, a receiver, a monitor, or a physical layer processing unit.The higher layer processing unit 14 is also referred to as a measurementunit or a controller.

The higher layer processing unit 14 outputs uplink data (which may be asreferred as a transport block) generated by a user operation or thelike, to the radio transmission and/or reception unit 10. The higherlayer processing unit 14 performs processing for some or all of theMedium Access Control (MAC) layer, the Packet Data Convergence Protocol(PDCP) layer, the Radio Link Control (RLC) layer, and the Radio ResourceControl (RRC) layer.

The medium access control layer processing unit 15 included in thehigher layer processing unit 14 performs processing for the MediumAccess Control layer (MAC layer). The medium access control layerprocessing unit 15 controls transmission of a scheduling request, basedon various types of configuration information/parameters managed by theradio resource control layer processing unit 16. The medium accesscontrol layer processing unit 15 may control transmission of a beamrecovery request. The medium access control layer processing unit 15 maycontrol transmission of a beam pair link status report.

The radio resource control layer processing unit 16 included in thehigher layer processing unit 14 performs processing for the RRC layer(radio resource control layer). The radio resource control layerprocessing unit 16 manages various types of configurationinformation/parameters of its own apparatus. The radio resource controllayer processing unit 16 sets various types of configurationinformation/parameters based on higher layer signaling received from thebase station apparatus 3. Namely, the radio resource control layerprocessing unit 16 sets the various types of configurationinformation/parameters in accordance with the information indicating thevarious types of configuration information/parameters received from thebase station apparatus 3.

The radio transmission and/or reception unit 10 performs processing forthe physical layer, such as modulation, demodulation, coding, decoding,and the like. The radio transmission and/or reception unit 10demultiplexes, demodulates, and decodes a signal received from the basestation apparatus 3, and outputs the information resulting from thedecoding to the higher layer processing unit 14. The radio transmissionand/or reception unit 10 generates a transmit signal by modulating andcoding data, and transmits the generated signal to the base stationapparatus 3. The radio transmission and/or reception unit 10 may have afunction of receiving information for identifying a configuration ofmultiple reference signals in a certain cell. The radio transmissionand/or reception unit 10 may have a function of receiving multiplereference signals. The radio transmission and/or reception unit 10 mayhave a function of monitoring reception qualities of multiple downlinkbeam pair links based on the received one or more reference signals.

The RF unit 12 converts (down-converts) a signal received via theantenna unit 11 into a baseband signal by orthogonal demodulation andremoves unnecessary frequency components. The RF unit 12 outputs theprocessed analog signal to the baseband unit.

The baseband unit 13 converts the analog signal input from the RF unit12 into a digital signal. The baseband unit 13 removes a portioncorresponding to a Cyclic Prefix (CP) from the digital signal resultingfrom the conversion, performs Fast Fourier Transform (FFT) of the signalfrom which the CP has been removed, and extracts a signal in thefrequency domain.

The baseband unit 13 generates an OFDM symbol by performing Inverse FastFourier Transform (IFFT) of the data, adds the CP to the generated OFDMsymbol, generates a baseband digital signal, and converts the basebanddigital signal into an analog signal. The baseband unit 13 outputs theanalog signal resulting from the conversion, to the RF unit 12.

The RF unit 12 removes unnecessary frequency components from the analogsignal input from the baseband unit 13 using a low-pass filter,up-converts the analog signal into a signal of a carrier frequency, andtransmits the up-converted signal via the antenna unit 11. The RF unit12 amplifies power. The RF unit 12 may have a function of determining atransmit power of the uplink signal and/or the uplink channeltransmitted in the serving cell. The RF unit 12 is also referred to as atransmit power control unit.

FIG. 13 is a schematic block diagram illustrating a configuration of thebase station apparatus 3 according to the present embodiment. Asillustrated in the drawing, the base station apparatus 3 includes aradio transmission and/or reception unit 30 and a higher layerprocessing unit 34. The radio transmission and/or reception unit 30includes an antenna unit 31, an RF unit 32, and a baseband unit 33. Thehigher layer processing unit 34 includes a medium access control layerprocessing unit 35 and a radio resource control layer processing unit36. The radio transmission and/or reception unit 30 is also referred toas a transmitter, a receiver or a physical layer processing unit. Acontroller controlling operations of the units, based on variousconditions may be separately provided. The higher layer processing unit34 is also referred to as a terminal control unit.

The higher layer processing unit 34 performs processing for some or allof the Medium Access Control (MAC) layer, the Packet Data ConvergenceProtocol (PDCP) layer, the Radio Link Control (RLC) layer, and the RadioResource Control (RRC) layer.

The medium access control layer processing unit 35 included in thehigher layer processing unit 34 performs processing for the MAC layer.The medium access control layer processing unit 35 performs processingfor a scheduling request, based on various types of configurationinformation/parameters managed by the radio resource control layerprocessing unit 36. The medium access control layer processing unit 35may perform processing for the beam recovery request. The medium accesscontrol layer processing unit 35 may perform processing for the beampair link status reporting.

The radio resource control layer processing unit 36 included in thehigher layer processing unit 34 performs processing for the RRC layer.The radio resource control layer processing unit 36 generates, oracquires from a higher node, downlink data (transport blocks) allocatedon a physical downlink shared channel, system information, an RRCmessage, a MAC Control Element (CE) and the like, and outputs thegenerated or acquired data to the radio transmission and/or receptionunit 30. The radio resource control layer processing unit 36 managesvarious types of configuration information/parameters for each of theterminal apparatuses 1. The radio resource control layer processing unit36 may set various types of configuration information/parameters foreach of the terminal apparatuses 1 via the higher layer signal. Namely,the radio resource control layer processing unit 36 transmits/broadcastsinformation indicating various types of configurationinformation/parameters. The radio resource control layer processing unit36 may transmit/broadcast information for identifying a configuration ofmultiple reference signals in a certain cell.

The radio transmission and/or reception unit 30 has a function totransmit multiple reference signals. The radio transmission and/orreception unit 30 may also have a function of receiving a schedulingrequest transmitted, from the terminal apparatus 1, using any one ofmultiple scheduling request resources configured by the higher layerprocessing unit 34. The radio transmission and/or reception unit 30 mayalso have a function of transmitting information for identifying aconfiguration of multiple reference signals in a certain cell. Some ofthe functions of the radio transmission and/or reception unit 30 otherthan the above are similar to those of the radio transmission/receptionunit 10, and hence a description thereof is omitted. Note that, in acase that the base station apparatus 3 is connected to one or moretransmission reception points 4, some or all of the functions of theradio transmission and/or reception unit 30 may be included in each ofthe transmission reception points 4.

Further, the higher layer processing unit 34 transmits (transfers) orreceives control messages or user data between the base stationapparatuses 3 or between a higher network apparatus (MME, Serving-GW(S-GW)) and the base station apparatus 3. Although, in FIG. 9, otherconstituent elements of the base station apparatus 3, a transmissionpath of data (control information) between the constituent elements, andthe like are omitted, it is apparent that the base station apparatus 3is provided with multiple blocks, as constituent elements, includingother functions necessary to operate as the base station apparatus 3.For example, a Radio Resource Management layer processing unit or anapplication layer processing unit exist in the higher layer processingunit 34. The higher layer processing unit 34 may also have a function ofconfiguring multiple scheduling request resources correspondingrespectively to multiple reference signals transmitted from the radiotransmission and/or reception unit 30.

The “units” in the drawing refer to constituent elements to provide thefunctions and the procedures of the terminal apparatus 1 and the basestation apparatus 3. Such a constituent element may be represented bydifferent terms such as a section, a circuit, a constituting device, adevice, a unit, and the like.

Each of the units designated by the reference signs 10 to 16 included inthe terminal apparatus 1 may be configured as a circuit. Each of theunits designated by the reference signs 30 to 36 included in the basestation apparatus 3 may be configured as a circuit.

Aspects of the terminal apparatus 1 and the base station apparatus 3according to an aspect of the present invention will be described below.

(1) A first aspect of the present invention is a terminal apparatus 1including a controller 14 for configuring multiple beam pair links formonitoring a downlink control channel, a monitor unit 10 for monitoringa quality of each of the multiple beam pair links, and a trigger controlunit 14 for triggering a beam pair link status reporting in a case thata beam pair link failure is detected in one or more beam pair linksamong the multiple beam pair links, in which the trigger control unit 14cancels the triggered beam pair link status reporting on a certaincondition.

(2) In the first aspect of the present invention, the certain conditionmay be that a MAC PDU for transmission includes the beam pair linkstatus report.

(3) In the first aspect of the present invention, a scheduling requestmay be triggered based on that the beam pair link status reporting istriggered.

(4) In the first aspect of the present invention, a beam recoveryrequest may be triggered based on that the beam pair link statusreporting is triggered.

(5) In the first aspect of the present invention, a random accesspreamble procedure may be initiated in a case that the triggered beamrecovery request is pending and the terminal apparatus 1 does not have aphysical uplink resource valid for the beam recovery request.

(6) In the first aspect of the present invention, the monitor unit 10may monitor the quality of each of the multiple beam pair links, basedon a reference signal associated with the corresponding beam pair link.

(7) A second aspect of the present invention is a terminal apparatus 1including a controller 14 for configuring multiple beam pair links formonitoring a downlink control channel, a monitor unit 10 for monitoringa quality of each of the multiple beam pair links, and a trigger controlunit 14 for triggering a beam recovery request in a case that a beampair link failure is detected in one or more beam pair links among themultiple beam pair links, in which the trigger control unit 14 cancelsthe pending beam recovery request on a certain condition.

(8) In the second aspect of the present invention, the certain conditionmay be that a MAC PDU is assembled and the MAC PDU includes a beam pairlink status report.

(9) In the second aspect of the invention, the certain condition may beto receive an uplink grant associated with the beam recovery request.

(10) In the second aspect of the present invention, the certaincondition may be that the triggered beam recovery request is pending andthe terminal apparatus 1 does not have a physical uplink resource validfor the beam recovery request.

(11) In the second aspect of the present invention, a random accesspreamble procedure may be initiated in a case that the triggered beamrecovery request is pending and the terminal apparatus 1 does not have aphysical uplink resource valid for the beam recovery request.

(12) In the second aspect of the present invention, the terminalapparatus 1 includes a counter 14 incrementing every time the beamrecovery request is transmitted, in which the random access preambleprocedure may be initiated in a case that a value of the counter 14 is apredetermined value.

(13) In the second aspect of the present invention, the certaincondition may be that the value of the counter 14 is the predeterminedvalue.

(14) In the second aspect of the present invention, the monitor unit 10may monitor the quality of each of the multiple beam pair links, basedon a reference signal associated with the corresponding beam pair link.

(15) A third aspect of the present invention is a terminal apparatus 1including a receiver 10 receiving, from the base station apparatus 3, asignal including first information indicating a resource of each ofmultiple downlink control channel regions associated with each of themultiple reference signals, and receiving, from the base stationapparatus 3, a signal including second information configuring one ormore of the multiple downlink control channel regions, and a monitorunit 10 for monitoring the downlink control channel for decoding in thedownlink control channel region based on the first information and thesecond information.

(16) In the third aspect of the present invention, a quality of a linkmay be monitored in the downlink control channel region based on thefirst information and the second information.

(17) In the third aspect of the present invention, the first informationmay be included in an RRC message and the second information may beincluded in a MAC CE.

(18) A fourth aspect of the present invention is a base stationapparatus 3 including a reference signal generation unit 10 generatesmultiple reference signals to be transmitted to the terminal apparatus1, and a transmitter 10 for transmitting a signal including firstinformation indicating a resource of each of multiple downlink controlchannel regions associated with each of the multiple reference signals,transmitting a signal including second information indicating, to theterminal apparatus 1, one or more of the multiple downlink controlchannel regions, and transmitting the downlink control channel in thedownlink control channel region based on the first information and thesecond information.

A program running on an apparatus according to an aspect of the presentinvention may serve as a program that controls a Central Processing Unit(CPU) and the like to cause a computer to operate in such a manner as torealize the functions of the above-described embodiment according to thepresent invention. A program or information handled by the program istransitorily stored in a volatile memory such as a Random Access Memory(RAM), a non-volatile memory such as a flash memory, a Hard Disk Drive(HDD), or other storage device systems.

Note that a program for realizing the functions of the embodimentaccording to an aspect of the present invention may be recorded in acomputer-readable recording medium. The functions may be realized bycausing a computer system to read the program recorded in the recordingmedium for execution. Note that the “computer system” herein refers to acomputer system built into the apparatuses, and the computer systemincludes an operating system and hardware components such as aperipheral device. The “computer-readable recording medium” may includea semiconductor recording medium, an optical recording medium, amagnetic recording medium, a medium dynamically holding a program for ashort time, or other computer-readable recording media.

The respective functional blocks or features of the devices used in theabove-described embodiment may be implemented or performed by anelectrical circuit, for example, an integrated circuit or multipleintegrated circuits. An electric circuit designed to perform thefunctions described in the present specification may include ageneral-purpose processor, a Digital Signal Processor (DSP), anApplication Specific Integrated Circuit (ASIC), a Field ProgrammableGate Array (FPGA), or other programmable logic devices, discrete gatesor transistor logic, discrete hardware components, or a combinationthereof. The general-purpose processor may be a microprocessor, aprocessor of known type, a controller, a micro-controller, or a statemachine. The electrical circuit described above may be constituted by adigital circuit, or an analog circuit. Furthermore, in a case that withadvances in semiconductor technology, a circuit integration technologyappears that replaces the present integrated circuits, one or moreaspects of the present invention can use a new integrated circuit basedon the technology.

Note that the invention of the present patent application is not limitedto the above-described embodiments. In the embodiment, apparatuses havebeen described as an example, but the invention of the presentapplication is not limited to these apparatuses, and is applicable to aterminal apparatus or a communication apparatus of a fixed-type or astationary-type electronic apparatus installed indoors or outdoors, forexample, an AV apparatus, a kitchen apparatus, a cleaning or washingmachine, an air-conditioning apparatus, office equipment, a vendingmachine, and other household apparatuses.

The embodiments of the present invention have been described in detailabove referring to the drawings, but the specific configuration is notlimited to the embodiments and includes, for example, an amendment to adesign that falls within the scope that does not depart from the gist ofthe present invention. Furthermore, various modifications are possiblewithin the scope of one aspect of the present invention defined byclaims, and embodiments that are made by suitably combining technicalmeans disclosed according to the different embodiments are also includedin the technical scope of the present invention. Furthermore, aconfiguration in which constituent elements, described in the respectiveembodiments and having mutually the same effects, are substituted forone another is also included in the technical scope of the presentinvention.

INDUSTRIAL APPLICABILITY

An aspect of the present invention can be utilized, for example, in acommunication system, communication equipment (for example, a cellularphone apparatus, a base station apparatus, a radio LAN apparatus, or asensor device), an integrated circuit (for example, a communicationchip), or a program.

REFERENCE SIGNS LIST

-   1 (1A, 1B) Terminal apparatus-   3 Base station apparatus-   4 Transmission reception point (TRP)-   10 Radio transmission and/or reception unit-   11 Antenna unit-   12 RF unit-   13 Baseband unit-   14 Higher layer processing unit-   15 Medium access control layer processing unit-   16 Radio resource control layer processing unit-   30 Radio transmission and/or reception unit-   31 Antenna unit-   32 RF unit-   33 Baseband unit-   34 Higher layer processing unit-   35 Medium access control layer processing unit-   36 Radio resource control layer processing unit-   50 Transceiver unit (TXRU)-   51 Phase shifter-   52 Antenna element

1-8. (canceled)
 9. A terminal apparatus comprising: reception circuitryconfigured and/or programmed to; receive, from a base station apparatus,a radio resource control (RRC) message which indicates information foreach of multiple downlink control channel resources, receive, from abase station apparatus, a medium access control (MAC) control elementwhich indicates one of the multiple downlink control channel resources,and monitoring circuitry configured and/or programmed to receive, from abase station apparatus, a physical downlink control channel based on theRRC message and the MAC control element; wherein the informationincludes an index which indicates one of the multiple downlink controlchannel, frequency resource information and quasi-co-location (QCL)information.
 10. A base station apparatus comprising: transmissioncircuitry configured and/or programmed to; transmit, to a terminalapparatus, a radio resource control (RRC) message which indicatesinformation for each of multiple downlink control channel resources,transmit, to the base station apparatus, a medium access control (MAC)control element which indicates one of the multiple downlink controlchannel resources, and transmit, to the terminal apparatus, a physicaldownlink control channel based on the RRC message and the MAC controlelement; wherein the information includes an index which indicates oneof the multiple downlink control channel, frequency resource informationand quasi-co-location (QCL) information.
 11. A communication method usedfor a terminal apparatus, the communication method comprising:receiving, from a base station apparatus, a radio resource control (RRC)message which indicates information for each of multiple downlinkcontrol channel resources, receiving, from a base station apparatus, amedium access control (MAC) control element which indicates one of themultiple downlink control channel resources, and receiving, from a basestation apparatus, a physical downlink control channel based on the RRCmessage and the MAC control element; wherein the information includes anindex which indicates one of the multiple downlink control channel,frequency resource information and quasi-co-location (QCL) information.12. A communication method used for a base station apparatus, thecommunication method comprising: transmitting, to a terminal apparatus,a radio resource access (RRC) message which indicates information foreach of multiple downlink control channel resources, transmitting, tothe base station apparatus, a medium access control (MAC) controlelement which indicates one of the multiple downlink control channelresources, and transmitting, to the terminal apparatus, a physicaldownlink control channel based on the RRC message and the MAC controlelement; wherein the information includes an index which indicates oneof the multiple downlink control channel, frequency resource informationand quasi-co-location (QCL) information.